Kids in a Room

Yesterday, Bill and I went to Southern Pines to see his parents and his visiting sisters. Bill's sisters, Jeanne and Sally, are visiting with each of their children, Tyler and Matthew. We went to a lovely brunch at the Mid Pines Country Club. The kids were very well behaved and we all had a nice time. After brunch, we went back to his parent's home. Why is it that if there are children in a room with a bunch of adults there is no adult conversation? We just really sat around watching the play and being annoyed by their toys. No one really speaks except when related to the kids. Don't get me wrong, I love seeing both kids. I just wonder why this phenomena always happens.